Also, for which spoken language? "The letter Ä... In Finnish and Turkmen this is always [æ]; in Swedish and Estonian regional variation, as well as the letter's position in a word, allows for either [æ] and [ɛ]. In Slovak Ä stands for [ɛ]": en.wikipedia.org/wiki/%C3%84
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Danny BeckettApr 13 '13 at 22:39

@Spoken language: Thank you, I didn't think of this. What would you suggest, to make it internationally solid? If this is not possible, I would focus on English, Spanish, French.
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user1625837Apr 13 '13 at 22:53

Normalize seems to provide a great algorithm, thank you. Maybe this is also available for a JVM-suitable language?
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user1625837Apr 13 '13 at 23:11

@user1625837 of course there will be other problems like أحمد‎ => ahmad or ahmed or ahmet. (arabic spokens, If I am wrong please correct me)
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I4VApr 13 '13 at 23:16

Sounds reasonable. The only thing I actually need is a function that always returns an elegant result (elegant in shape -- that is no % encoding or something like that --, but not necessarily elegant in meaning). In case of need, the user can decide to rename her/his name.
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user1625837Apr 13 '13 at 23:22